Allergy is characterised by a local or systemic inflammatory response to allergens. Allergic conjunctivitis is a disorder that is characterized by the clinical signs and symptoms of eye itching, redness, tearing, and swelling. An estimated 20% of the population in the United States suffer from inflammation of the eye. The signs and symptoms of allergic conjunctivitis can significantly impact the quality of life of patients, from social interactions, productivity at work and school, to the ability to perform visual tasks such as working on a computer or reading.
Currently, available pharmaceutical treatments for inflammation of the eye or symptoms of inflammation of the eye include (1) antihistamines, (2) drugs that block the release of histamine and other substances from the mast cell (e.g., mast cell stabilizers), (3) drugs with multiple modes of action (e.g. antihistamine/mast cell stabilizing agents), and (4) drugs that can actively constrict blood vessels thus reducing redness and swelling (e.g., vasoconstrictors). Additionally, artificial tears have been used to wash the eye of allergens.
The desirability of a particular treatment for inflammation of the eye can be measured against the following factors (1) efficacy at onset of action, (2) duration of action, (3) efficacy at controlling signs and symptoms of allergic conjunctivitis, and (4) comfort of the drop when instilled in the eye.
Many patients desire an effective treatment by ingredients that are from natural sources and prefer treatment that avoids or reduces the amount of traditional active pharmaceutical ingredients used.
Alginate, for the purpose of this application is a polysaccharide that comprises β-D-mannuronic acid and α-L-guluronic acid monomers or salts or derivatives of such acids or salts.

Some alginate polymers are block copolymers with blocks of the guluronic acid (or salt) monomers alternating with blocks of the mannuronic acid (or salt) monomers. Some alginate molecules have single monomers of guluronic acid (or salt) alternating with the comonomers of mannuronic acid (or salt). The ratio and distribution of the M and G components along with the average molecular weight affect the physical and chemical properties of the copolymer. See Haug, A. et al., Acta Chem. Scand. Vol. 20, 183-190 (1966). Alginate polymers have viscoelastic Theological properties and other properties that make it suitable for some medical applications. See Klock, G. et al., “Biocompatibility of manurononic acid-rich alginates,” Biomaterials, Vol. 18, No. 10, 707-713 (1997).
The use of alginate as a thickener for topical ophthalmic use is disclosed in U.S. Pat. No. 6,399,605 and U.S. Patent Application Publication 2003/0232089 incorporated herein by reference in their entirety. In U.S. Pat. No. 5,776,445, alginate is used as a drug delivery agent that is topically applied to the eye. Particularly, the amount of guluronic acid in the alginate was taught to exceed 50%.
U.S. Patent Application Publication No. 2003/0232089 teaches a dry-eye formulation that contains two polymer ingredients including alginate.
WO2005/082333 discloses the use of sodium alginate in a viscoelastic formulation for ophthalmic surgery.
U.S. patent application Ser. No. 11/475,277 filed Jul. 1, 2005 teaches a dry eye formulation comprising alginate and a polyol. The alginate formulation contained certain ranges of Mannuronic:Guluronic ratios that were considered preferable.
Mirshafiey, et al., “Sodium alginate as a novel therapeutic option in the experimental colitis,” Scand. J. Immunol., Vol. 61, 316-321 (2005) establishes that alginate inhibits cytokine, MMP2 and eicosanoid activity in a rat model suggesting that alginate could be useful to reduce inflammation in the colon of a rat.
In view of the above, it would be desirable to provide an eye-drop solution that will better alleviate the symptoms of inflammation of the eye and that is safe, convenient and economical to use. In particular, it would be highly desirable to develop a product having significantly greater duration of efficacy, in order to significantly decrease the number of times that the product may need to be administered to the eye, over the course of a day, in order to effectively treat the symptoms of inflammation of the eye. The present invention addresses these and other needs.